Telephone system



Jan. 30, 1934. H. M. FRIENDLY TELEPHONE SYSTEM 14 Sheets-Sheet 1 FiledSept. 22, 1917 fl uuumw nun uuunwknu s v I wan-row Jan. 30, 1934. H. M.FRIENDLY l,944,91i

TELEPHONE SYSTEM IHHHIIIIIIHI bi 'llllllllfi llllllllllllllllIHIIIIIIIIHIII oz D- INVENTOR:

ELSE-SIG J. 30,1934; H. M. FRIENDLY TELEPHONE SYSTEM Filed Se t. 22.1917 1.4 Sheets-Sheet 3 L II II II llll ll IIIIIHI g3? llllllllllllllllIIIIIIIIIHHIII IHIIIIHIIIIIII II Illllllllllillll llL a} II II "II II I]II" II I! "ll III] "II in; x.

llllllllllll II II IIIHHIIHI IISURIIIIIHIIIIIIIIHIII 1 & zllllllllllllllll Illlllllllllllll ll Illllllllllllllfill lHlllllllll llL II II II [III lllllllllli I llHllllllHl -llllllllllllllllIllllllllllllllfill llllllllllllllll II -l|||lH||l||lHl \NVENTC R Jan.30, 1934.

H. M. FRIENDLY TELEPHONE SYSTEM Filed Sep tL 22, 1917 14 Sheets-Shem 4lNVENTOR ml L a Q Jan. 30, 134.

H. M. FRIENDLY TELEPHONE SYSTEM Filed Sept. 22, 1917 14 Sheets-Shqet 5 Lz E Q n m I EJE Jan. 30, 1934.

H. M. FRIENDLY 1,944,911

TELEPHONE SYSTEM I 14 Sheets-Sheet 6 Filed Sept. 22. 1917 lllllIHIIIIHHIIIII II IIIIIIIHIIIIIII llllllilllllllllll Q 99 l NVENTOR=Jam:o 3Q, 1934.

H. M. FRIENDLY TELEPHONE SYSTEM Filed Sept. 22, 1917 14 Sheets-Sheet, 7

I NVENTOR Jgn 30, 1934. H. M. FRIENDLY TELEPHONE SYSTEM Filed Sept. 22.1917 14 Sheets-Sheet 1o JQUOJ \NVENTOR Jan." 30, 1934. H. M. FRIENDLY1,944,911

' TELEPHONE SYSTEM Filed Sept. 22. .1917 i4 Sheets-Sheet 12 *a 4 g g HIHH f |||||||||||||||||l IHHHHIIIIHIII llllllllllllllll lhf m a? i,- Q 3Q INVENTOR Jan. 30, 1934. H. FRIENDLY 1,944,911

' TELEPHONE SYSTEM Filed Sept. 22, 1917 14 Sheets-Sheet 13 Jan. 30, 1934w H; M. FRIENDLY 1 TELEPHONE sYs TEu Fil ed Sept. 22, 1917 14 sheets-shet 14 R's TELO. sz-r.

$1 U U E INVEHTOR= Patented Jan. 30, 1934 (PATENT OFFICE 1,944,911TELEPHONE SYSTEM Herbert M. Friendly, Portland, 0reg.; Milton S.Friendly and Central Republic Trust Company, executors of said HerbertM. Friendly, deceased Application September 22, 1917 Serial No. 192,713

29o Claim st My invention relates to what are known as automaticsystems. It further particularly-refers to remote control switching oflong distance lines as distinct from local line switching. However, ithas certain applications to local line switching.

The switching of long distance telephone lines by automatic or remotecontrol means as contemplated by my invention has certain novelfunctions and advantages in the handling of traific,

which will be clear from the following descrip-' tions of typical formsshown'and described here for illustration only and not intended as anexhaustive presentation of the possible forms with in the scope of myinvention.

Among the novel features and objects of my in-' vention are: r I

Means for obtaining supervision back from the terminating end to theoriginating end; means for selecting lines through aseries of stationsand receiving confirmation that calling impulses are 'going through;means for releasing the switches at the terminus without releasingintermediate switches, enabling a second number to be set up forthwith;means for selectively releasing back to any desired switching point andto again go forward as desired; means for introducing or removing arepeating coil or amplifier at will at any switching point; means forrestraining the connector switch where a line or group of lines soughtarebusy and then allowing the connector to select and seize the line (orfirst dis engaged line of a group) when non-busy; means to allow a busytone to be projected back to the calling operator, said busy tonedenoting how many, (if any) are waiting ahead and to allow '1 ends oflines, 6f a group.

the waiting parties to obtain access to the desired lines in the orderof their attempts to reach one of them; means whereby operator'users ofI busy lines are notified when all lines ina group are busy, or when oneor more operators are waiting; means to signal at will on connected.

, access to a waiting line and then return it to its waiting position,or outof its-waiting positionas desired; means to allow an intermediateoperator to advance her place in waiting for a line to become disengagedahead of operators at remote points; means to show the idle or busystate of a line and to prevent interference by impulsing when a busyline is connected with inadvertently.

The functions hereinbefore set forth are novel so far as I am aware,though elements well known are used in part to accomplish saidfunctions.

There are other points of novelty as to functions and methods which willbecome apparent from the description and subjoined drawings. Thedrawings are as follows:-

Fig. 1 is a line and associated 1st toll selector together with controlswitch.

Fig. 1A is a telephone set associated with a switching plug.

Fig. 1B is an amplifier which may be substituted for repeating'coils atsection lines :r-u.

Fig. 2 is a 2nd toll selector.

Fig. 2A is a repeating coil which may be inserted at section lines.r'2-y2 and z2-'-u2.

Fig. 2B shows the essential moving elements of a selector switch shownin Fig.3.

Fig. 2C is an adaptation of Fig. 4 to enable a waitingline to beconnected with by an operator at an intermediate station.

Fig. 3 is a selector switch.

Fig. 3A is a modification of a portion of Fig. 3.

shown in Fig. 3.

Fig. 5 shows equipments at opposite ends of a line in one element of mysystem.

Fig. 5B is a signal device mechanism.

Fig. 6 is a 1st toll selector and control switch for use with Fig. 5.Fig. 6 also cooperates with Fig. 2.

Fig. '7 is a modification of Fig. 5. It attaches at indicated terminalsabove Fig. 5.

Fig. 7B is abank arrangement for opposite Fig. 8 is a bank and terminalplan of a connection from a. first selector to a local line. Fig. 9 is abank and terminal plan of a-con- 'nection from a first selector to tolllines.

Fig. 10 is a duplex combination scheme. Fig. 11. is a localtoilselector.

"Fig. 12 is a B switching circuit.

Fig. 12A is a springjack and subscriber's equipment.

Fig.13 is a device for translating from toll three-wire operation tolocal two-wire operation.

Fig. 14 is a modification of the line equipmen of Fig. 5.

Fig. 15 is a modification of the cord equipmen at the left of Fig. 5.

Fig. 161s a local toll selector.

Fig. 17 is a direct point duplex repeater scheme.

Fig. 4 is a bank arrangement of the selector the first set of bankcontacts.

Fig. 18 is an intermediate operators extending circuit.

Fig. 18A is a modification of Fig. 19 to enable selector terminals to becut off.

Fig. 19 is a selector together with control switch. It attachesatindicated terminals above Fig. 20.

Fig. 20 is a modification of the left portion of Fig. 7.

Fig. 21 is a modification of Fig. 3 and Fig. 4.

Fig. 22 is a B switching circuit.

For convenience designations are used as:

P1, denoting private conductor; P2, denoting impulsing conductor; D1denoting the polechanger moving point conductor and D2 denotingtheneutral point conductor of duplex sets.

Switching elements termed selectors and connectors referred to hereinare'of the coordinate type of the organization and class as has beenmade and extensively sold for use in local automatic exchanges by theAutomatic Electric Company of Chicago, Illinois, and set forth ingeneral as regards mechanical arrangement in U. S. Letters Patent'Nos.815,321 and 815,176 respectively, granted to A. E. Keith and J. and C.J. Erickson, co-inventors, March 13, 1906. However, the mechanical andelectrical details and the functions attained are radically modified inthe adaptation to the present invention.

Referring to Figs. 1, 1A, 2, 2A, 2B, 3, 3A and 4; a call will be tracedfrom the plug N through to springjacks N4 and M4.

Upon inserting plug N into springjack J spring w completes a circuitfrom terminals p through impulse spring of sending device m to ground.This will allow line relay A to energize by way of line conductor andterminal t. The tone source in Fig. 1 will be applied through the loweroff-normal spring to the minus line conductor, audible through thecalling plug N. When the selector Fig. 1 first operates, the tone sourcewill be disassociated. Manipulating sending device m to open and closeits contacts and u will cause relay A to deenergize successively inaccordance with the interruptions introduced thereby. The lower springof relay A will close against its upper contact-point long enough tokeep retarded relay B energized, thus closing the circuit from ground tothe vertical magnet through to lower contact of relay A by way ofcontact on relay D while relay D remains unenergized. Thus, thesuccessive breakings of contacts k and u in impulse sending device mwill correspondingly actuate the vertical magnet in the well knownmanner to move the shaft of the switch vertically. Upon the relay Aremaining closed for a prolonged period at the termination of the seriesof circuit openings and closings constituting a digit, relay C will be-'come deenergized by reason of open circuit at lower contact of relay A.Relay E will actuate because of current derived through it leadingthrough upper off-normal contacts and armature of relay C to ground onarmature of relay B upon the first energization of relay C in. serieswith the vertical magnet. When relay C deenergizes after the lastvertical impulse, its armature applies ground to the rotary magnet.causing it to actuate and unlock E and step the wipers into engagementwith If a busy ground is encountered by the wiper ,f the relay E willderive direct ground from said wiper by way of the contacts on therotary magnet and middle upper armature on relay D. causing E tore-actuate and cause the rotary magnet to re-actuate and drive the shaftone step; this functioning until .a non-busy, non-grounded bank contactis encountered by wiper j. The ground encountered bywiper j" serves toshortcircuit relay D, :preventing it from actuating from. currentderived through E, but it will actuate upon the ground being removedupon a non-grounded contactbeing encountered by wiper I. Incidental tothe actuation of relay D the lines and impulse wire will be extended towipers e", d and 0" respectively, thereby extending the calling line tosecond selector Fig. 2 over bank contactsof Fig. 1. Assuming thatinterruptions constituting digit 4 had been sent from sending device m,wipers carried by the shaft. will have been stepped up four levels, and

wipers e" and d will have been extended to the line bank contacts 0' andd and wipers c" and I will have been extended to bank contact :5. 9'corresponds to P3 in Fig. 2. g" corresponds to P2 in Fig. 2. hcorresponds to P1 in Fig. 2'. 0 corresponds to minus line in Fig. 2. dcorresponds to plus line in Fig. 2. 'Assuming that an interruptionconstituting the digit 1 is now sent on impulse sending device m, relayA will be caused to operate in the manner previously described for thepurpose of extending ground to relay B2. This circuit may be traced fromcontacts on relay A, through contacts on relay D, through wiper 0', overbank contacts 9 to terminal P2 on Fig. 2, through contacts on relay A2to relay B2. The method of stepping the shaft of switch Fig. 2 up to the1st level from contacts on relay B2 and there rotating the shaft on to anonbusy set of contacts is accomplished in the well known manner forsimilarly situated relays. Incidental to the shaft being rotated to anonbusy trunk contact relay A2 will be actuated for the purpose ofdisassociating P2 from the free pole of relay B2 and extending it towiper c2. Incidental to the operation of relay A2 plus and minus linesand P1 are extended to wipers e2, d2 and b2respectively. The free poleof relay J2 extends to wiper a2. a2 corresponds to terminal P3 in Fig.3. b2 corresponds to P1 in Fig. 3. e2 corresponds to P2 in Fig. 3. (1'2corresponds to minus line in Fig. 3. e2 corresponds to plus line in Fig.3.

Referring to Fig. 1 it will be noted that ground l is extended fromcontacts on relay B through contacts on relay D, through wiper f", overbank contact h", through terminal P1 in Fig. 2, through contacts onrelay A2, through wiper b2, over bank contact b2 to terminal -P1 in Fig.3. Referring to Fig. 2, the impulse wire may be traced from contacts onrelay A2 through wiper c2, over bank contact e2, through terminal P2 inFig. 3, through contacts on relay C3 to the winding of relay D3, causingthe latter relay to become actuated. Assuming that interruptionsconstituting the digit 2 are now sent from the impulse sending device mthe shaft of Fig. 3 will be stepped up to the 2nd level in response tothe interruptions introduced by relay D3 and there rotated to a nonbusyline contact in the well known manner for relay C3 will be actuated forthe purpose of ex-' tending terminal P1 through the winding of relay B3,through contacts on relay C3 to the free pole of relay D3, causing saidrelays B3 and D3 to become actuated. Incidental to the actuation ofrelay B3 ground will be extended through the contacts of the latterrelay to winding of relay A3 to terminal P3 of Fig. 3 to bank contacta2, over wiper a2 to the free pole of relay J2, causing the latter relayto become actuated. Incidental to the actuation of relay J2 ground willbe extended from contacts on relay K2 through contacts on relay'J2 tothe free pole of solenoid of interrupter device L2.v The actuation ofsaid L2 will cause wiper L2 to be raised until said wiper L'2 has raisedto contacts 112 and n'2, thereby extending ground from contacts n2through wiper L'2 through contact n2, through contacts of relay K2 tothe free pole of the latter relay, causing said relay K2 to becomeactuated and remain so by reason of ground being extended from terminalP1 in Fig. 2 through contacts of relay H2 to contact on relay K2.Incidental to the actuation of relay K2 the circuit will be opened tothe free pole of solenoid L2. Upon the circuit being opened to the saidL2 wiper L'2 will be caused to move in a downward direction by gravity.Incidental to the downward course of said wiper L'2 ground will beextended from contacts 1V2, through said wiper L'2, through bankcontacts T2 and 1"2 to I the free pole of relay G2, causing said relayG2 to be actuated twice in succession (if but one contact were used as12, relay G2 would actuate one time only). Incidental to the actuationof relay G2 plus and minus lines of Fig. 2 will be opened to wipers d2and e2 said wipers d2 and c2 being extended to signaling current sourceG2 through contacts on said relay G2. Said signaling current is extendedfrom wipers d2 and c2 over bank contacts d2 and e '2. to minus and pluslines respectively'in Fig.3. through contacts on relay M3 to wiperszr3and 3/3 over bank contacts to line which is being called, therebycausing the signal device Df'4'on said line to be actuated. Thisis shownin Fig. 4, where the line leads from contacts 11:9 and i9, and signaldevice D"4 is connected on said line.

- Should the calling line desire to again project signaling current tothe called line the index number "11 maybe sent from the impulse sendingdevice, thereby causing the shaft wipers of the lower code switch shownin Fig. 1 to vbe rotated to the 11th rotary contact as describedhereinafter.- Ground may now be traced from.

contact 'on relay D, through winding on relay K, through contacton relayJ to wiper a, to bank contact n, over .wiper b through bank contact 1'to lug P3 in Fig. ,2 to the winding of relay H2.

Upon the above circuit being established, relays K- and H2 will becomeactuated; relay K for the purpose of extending ground to the releasemagnet of the'lower switch in Fig. l, and relay H2 for the purpose ofopening ground to the winding of relay K2,"thereby causing the latterrelay to be restored-to normal. Incidental to relay K2 being restored to'normal, the circuits will be again established as previously describedfor the purpose of extending signaling current from contacts on relay-G2through line wipers d" and e",

over bank contacts (1'2 and e2, through selector Fig. 3,aspreviouslydescribed, to the called line. If it isv assumed that therespective contacts 'of the first, and second levels in the sets ofbanksin Fig. 2 are tied togethergwith the exception of thesecond level ofthe'upper set of bank levels,

the latter bank lev'el being left dead, and that the digit 2 is sentfrom the sendingdevice as the second-digit, in lieu of l, no circuit canFig. 3) are seized, the groundon 103 received from contact on relay A ofFig. l is continued to the center of the line windings of repeating coilE4, over its said windings and line conductors in derivation t0 therespective outer terminals of the line windings of repeating coil D4,and through the center point of the said line windings of repeating coilD4 to the free pole of relay Z4, actuating said relay for the purpose ofcausing signal lamp L4 to glow. Connection to the line may then be madeby the use of a switching plug as N in Fig. 1, using the springjack N4.The said repeating coil, and also the repeating coil shown in Fig. 2Aconsists of two sets of seriesed windings inductively related, as forexample, the set of two windings shown on the left on the iron core areinductively related tothe set of two windings shown on the right on thesaid core. Therefore, currents constituting sound, which may traverseone set of two windings will be translated inductivelyto the" other setof two windings.

Thus, the calling party may selectively actuate either signal device D"4or L4. These devices may therefore be before operators situated apart.

Since the actuation of ringing control device L2 is dependent upon theactuation of relay J2 and relay J2 did not actuate by reason of its freepole finding an open bank contact no signaling current will be projectedfrom relay G2, by reason of its free pole remaining open at contacts r2matically in Fig. 3, contacts and wiring being omitted. The two releasesbeing independent the actuation of the rotary release magnet will onlyallow the shaft to rotate back to the first rotary posi'ion but not tonormal rotary position. The two release magnets acting together willallow the shaft to return to absolute normal position. The object of theparfial rotary release without vertical release will be explained in thefollowing description.

Referring to Fig. 4 it will be-noted that the free poles of relays B3,S3 and T3 are connected to bank contacts 4R, 4S and 4T respectively, the

saidbank contacts being what are commonly known as privates. Uponanysaid bank contacts being seized by private wiper'v3 groundis extendedover said wiper 123 to private bank contact, thence to free pole oftherelay connected to the respective private bank contact, thus acturelayT3, through contacts on relay S3, through contacts on relay R3, thenceto bank contact c3;

(and its multiples). Upon a next selector, as Fig. 3, trying to obtainaccess to one of the above group of lines ground on bank contact 03 willbe extended over wiper t3, through winding of relay T'3, through windingof relay W3, through winding of relay Z3, through winding of relay R3.When the above circuit is established said relays T'3, W3, Z3 and R3will become actuated. Incidental to the actuation of relay R'3 the freepole of battery will be disconnected from the winding of the rotarymagnet, through contacts associated with said rotary magnet. The saidfree pole of battery will be disconnected from the winding of relay G3as well as from the rotary magnet. The rotary magnet not receivingcurrent will remain inoperative. Incidental to the actuation of relay T3a tone will be extended to the negative line, said tone beinginterrupted uniformly, thereby denoting to the calling operator that theline calling has first choice as against subsequent calling lines.Incidental to the actuation of relay T3 ground will be extended throughits contacts over wiper 113, thence to bank contact d3; said bankcontact d3 being in multiple relation with other first bank contacts inthis particular group. Upon a subsequent calling line attempting to gainaccess to one of the above mentioned group of lines through anotherswitch similar to Fig. 3, ground will be extended from bank contact d3(and its multiples) over wiper a3 of said latter switch, throughcontacts on relay T'3, through winding of relay W3, through winding ofrelay Z3, through winding of relay R3, thence to the free pole ofbattery. Upon the above circuit being established relays W3, Z3 and R3of the said secondswitch similar to Fig. 3 will become actuated. Groundmay also be traced from bank contact 03 over wiper t3, through windingof relay T3 to winding of relay W3. Ground being extended as describedabove to winding of relay W3 will cause relay T3 to remain inactive. Theactuation of relay R3 will cause the same circuits to be established aspreviously described. Incidental to the actuation of relay W3 a tonewill be extended to the negative line; said tone being interrupted twicein succession, thereby denoting to the calling operator that the callingline has second choice as against any subsequent calling lines.Incidental to the actuation of relay W3 ground will be extended throughits contacts from contacts on relay T3 through contacts on relay H3,.through contacts on relay M3 to wiper 9:3, thence to bank contact e3,said bank contact being in multiple relation with other first bankcontacts in this particular group. Upon a subsequent calling lineattempting to gain access to one of the above mentioned group of linesthrough another switch; similar to Fig. 3, ground will be extended frombank contact 63 over wiper $3 of said latter switch, through contact onrelay M3, through contacts on relay H3, through contacts on relay W3,through winding of relay Z3, through winding of relay R'3, thence tofree pole of battery. It will be noted from the above circuit that relayT3 and relay W3 will be shunted from the circuit as previously describedin relation to T3. The operation of relay R3 will again establish thesame circuits as previously de-' scribed. Incidental to the operation ofrelay Z3 a tone will be extended to the negative line, said tone beinginterrupted three times in succession, thereby denoting to the callingoperator that the calling line has first choice as against subsequentcalling lines though two calling lines have first choice over thecalling line in the. order in which they attempted to reach the calledline or group. Incidental to the actuation of relay Z3 ground will beextended through its contacts, through contacts on relay W3, throughcontacts on relay T'3, through contacts on relay H3, through contacts onrelay M3, through wiper g3, thence to bank contact f3; said bank contact]3 being in multiple relation with otherbank contacts of this par-'ticular group. Upon a subsequent calling line attempting to gain accessto one of the above mentioned lines through another switch, similar toFig. 3, in the said group ground willbe extended from bank contact f3over wiper 113 of said latter switch, through contacts on relay M3,through contacts on relay H3, through contacts on relay T3, throughcontacts on relay W3, through contacts on relay Z3 to free pole ofrelayR3, causing the latter relay to become actuated for the purpose aspreviously described, relays T3, W3 and Z3 remaining in their normalpositions. In-' cidental to the actuation of relay R3 a tone will beextended through contacts on relay Z3, through contacts on relay R'3,thence to the negative line, said tone being steady will denote to thecalling operator that three (or more than the allowed number) operatorsare waiting for one of the lines in the group and that it will be of nopurpose to hold the line for turn as the connector will not bethereafter able to seize a line, so the connection must therefore bereleased for a subsequent attempt. Ground is extended from contacts onrelay E3, through contacts on relay Z3, through contacts on relay R3 tothe free pole I of the latter relay, causing said relay R3 to remain inan actuated position.

Fig. 3A shows a modification of'Fig. 3 in that the conductor includingthe condenser 325" is removed and a conductor leading from spring 3t ofrelay T3 is' run to relay Q3. From spring 3a a conductor leads throughcontacts 3d and 30 added to relay C3 and extended to terminal 3e. Thespecial tones indicated at the left of Fig. 3 are changed tospecial'interruptions. Thus positive battery will be applied to D2 inlieu of mm jecting a busy tone along the telephonic line conductors. Theapplication of the positive battery to said D2 will be apparent infurther descriptions as giving a flash signal to the calling operatorthrough her supervisory lamp or other associated lamp.

Should one of the lines of the particular group as mentioned becomedisengaged the corresponding relay associated with the private bankcontact will be restored to normal, thereby breaking the chain ground tobank contact 03. The selector having relays T'3, W3, Z3 and R3 actuatedby means of ground extended from bank contact 03 will immediately rotateuntil its wipers seize a nonbusy line. Relays T'3, W3 and Z3 having aretarded release characteristic will remain actuated an appreciablelength of time after actuating current has ceased. Relay R3 willimmediately restore to normal, closing the free pole of battery throughcontacts on rotary magnet to the winding of said rotary magnet, therebycausing the said rotary magnet to become actuated, extending groundthrough its contacts to the winding of relay L3. Upon relay L3 becomingactuated ground will be extended from first rotary oifnormal contactsthrough contacts of relay L3, over conductors to bank contacts 03 and(13 respectively. Upon the wipers of Fig; 3 seizing a nonbusy linecontact the rotary magnet circuit will be opened in the well knownmanner, thereby breaking the circuit to relay L3, said relay L3 haying aretarded release characteristic will remain actuated an appreciablelength of time, but upon restoring to normal ground will be removed frombank contact d3. 03- will still have ground connected to its contact aspreviously described when all linesare busy. Bank contact (13 has noground connected thereon, therefore the selector which had second choicewill now have first choice and the selector which had third choice willnow have second choice, leaving the third choice free to the firstsubsequent caller. Under the condition of no ground being associatedwith bank 1 .contact d3 selector which had second choice will nowreceive ground from bank contact-c3 over wiper t3 through winding ofrelay T3, through winding of' relay W3, through winding of relay Z3 tofree pole of relay R'3. This selector is now in position to receivefirst choice'to any line which may become idle in the group called for.Upon relay T3 becoming actuated ground will be disconnected from bankcontact e3. The selector which had third choice not receiving groundfrom bank conzact e3 will now receive'ground from bank contact (13,which permits relay W3 to become actuated; also relays Z3'and R'3 forthe purpose as described above.

Referring to Fig. 3, relay L3 will be actuated during the rotary motionof the shaftofFig. 3; thereby closing ground to the 11th rotary 0&-

' ing the 11th rotary off-normal contacts. Incidental to the closing ofthe said off-normal con-. tactsground will beextended'to the free poleof relay J3, causing the latter relay to become actuaafed for thepurpose of extending ground to the rotaryrelease magnet shown in partmechanical detail in Fig. 2B. This will allow the shaft to return to the1st rotary position; regardless of its vertical position which will notbe affected. This will allow the selector which has just been describedto return to its former position of first choice to this group of lines.Should there be selectors holding second and third positions waiting toseize a nonbusy line as previously described said second and thirdposition selectors will reperiod the relay L3 is actuated, this beingaccomplished by reason of ground being extended from the contacts ofrelay L3 to bank contact c3. The grounding of bank contact c3 willaccomplish the same result as when relays T3, R3 and S3 are actuated. g1

' Referring to Fig.- 4, shouldit be desired to reduce the numberpossible to wait on any group of lines, the switch-arms url and w' 4will be manipulated. As for instance it is desired to reduce the waitingselectorspossible from three to two, switch-arms m4 and w'4 will bethrown to con tacts m4 and m'4 respectively. 'Should it be desired toreduce the number possible to wait for any group of lines to one,switch-arms w4 and 10% 'will be thrown to contacts n.4 and 11/4respectively, and should it'be desired to not have any waiting selectorsswitch-arms 'w4 and w'4- will be thrown to contacts 7'4 and 1"4respectively. Ground from chain relays R3, S3 and T3 will be extended toswitch-arm 1424 and should-switcharm 104 be thrown on any of the abovemen'- tioned contacts'm4, n4 a nd is said ground will be extended tobank contacts corresponding to wipers leading to the" relays ,T3, .W3and Z3- It will be noted from the above and from previous descriptionsthat ground being extended to any of-the bank contacts as-abovementioned the corresponding relay; will not become actuated due to thefact that it is-shorted out of the circuit. Thus ifthe switch-arm w4 isin contactvrith i4 re'ay R'3fwi1l be the only relay to become actuated,thereby giving the final tone to the calling line, w'4 being groundedpermamently will extend said ground upon it being thrown to firstcontact .m4, to bank contact 13, thence over wiper 1'3 to the winding ofrelay R3, causing said relay R3 to become actuated for the purpose ofsubstituting the tone interrupted one time for the tone interrupted twotimes. If

switch-arm w'4 were manipulated to contact 12'4 ground would be extendedto bank contact 113. thence over wiper s3't o relay N3, causing saidrelay N3 to become actuated for the purpose of substituting the tonewhich is interrupted one time for the-one which is-interrupted threetimes.

Referring to Fig. 3, it will be noted that lamp signals A'3 and C'3 willbecaused to glow when a selector is in waiting to seize one of anyparticular group. Upon the first waiting selector seizing bank contactd3 groundwill be extended to lamp A'3. If there are two waitingselectors ground will be extended from bank contact e3 to lamp B3. Ifthere are three waiting selectors ground will be extendedfrom bankcontact f3 to lamp 0'3. The said lamps A-'3, 3'3 and C3 are for thepurpose of denoting to the intermediate operator how many'linesare'waiting to gain access to any certain group oflines. should theintermediate operator desire to gain first place over any callingoperator a switching'plug would be inserted in spring-jack D3 (whichactsas aswitch), closing contact 11"3, thereby extending ground to bankcontact 03. It will'be noted that when relays T3, R3 and S3 are actuatedground is also extended to bank contacts 03, but upon any line in thisparticular group becoming disengaged, the operator willknowfrom-observing the line busy lamps, as 5L, which line is availableand may then proceed to take the line through the regular linespringjack. :The plug willthen be removed from springjack D'3,-leavingany waiting selectors in their respective order'of waitin theirrespective positions during the v Referring to Fig.- l, the lower righthand poroperates from the A relay in the selectorat the top of the samefigureafter relay D has actuated. The code switch moves as many contactspaces as the A relay operates for eachv series constituting a digit,and then releases to normal position. The purpose of this switch memberis I to perform certain functions as will b'e hereinafter-described. v

Assuming that fourteen impulses are sent to relay A, ground will beextendedfiom back contact of said relay through contacts on relay B,through winding of relay D" to-rotarymagnet. The wiper a will beextended'to bank contact d, Ground may be tracedfrom-contacts' onrelayD, through winding of relay'K, through contacts on relay J, over wipera, through bank contact d to free pole of relay A, causing the latterrelay to become actuated for .the purpose of extending signaling currentto wipers d' ande". From the bank contacts registering with saidwipersthe path extends to other selectors and to any line called. Relay Ahaving a retarded release characteristic will remain actuated anappreciable length of time after its circuit has been broken. It will benoted .from the above description that relay K being in series in thecircuit with relay A said relay K will become actuated, therebyextending ground to the release magnet of the auxiliary code switch,causing the shaft and wipers of same to be restored to normal, whenrelay D has restored to normal.

Should it be desired to restore the selector on the same figure tonormal, regardless of how many switches may be following it in aconnection which may be established, a series of twelve impulses wouldbe transmitted, followed by the digits 3, 5 and 7. Upon sending theseries of twelve impulses ground will be extended from back contacts onrelay A through contacts on relay B, through winding on relay D, torotary magnet, causing the shaft and wiper a. to be moved in a rotarydirection to bank contact a. Ground will now be extended from contactson relay D through winding on relay K, through contacts on relay J,through wiper a, over bank contact a, thence to the winding of relay J.Upon the above circuit being established relays K and J will becomeactuated. Relay J will remain in a locked position and relay K willextend ground from its contacts to the release magnet of the codeswitch, causing the shaft and wipers thereof to be restored to normalposition. Upon the next digit, 3 being sent, ground will be extendedfrom the back contact of relay A through contacts on relay D, throughwinding of relay D, thence to the rotary magnet of the code switch. Uponshaft and wipers being rotated to the third contact ground'will beextended from contacts on relay D through winding of relay K, throughcontacts on relay J (said relay J being actuated), through wiper b, overbank contact e to the lower winding of relay F. Relay K and relay F willbecome actuated. Relay K for the purpose previously described and relayF for the purpose of extending the lower winding of relay G to bankcontact f. Relay F will remain actuated by reason of closing its upperwinding through its contacts to ground. Upon the next digit, 5, beingsent the shaft and wipers will be rotated to the 5th rotary contact.Ground may be again traced from contacts on relay D to winding of relayK, through contacts on relay J, through wiper b, over bank contact 1,through contacts on relay F to lower winding of relay G, causing saidrelays G and K to become actuated. Relay K for the purpose previouslydescribed and relay G for the purpose of extending the lower winding ofrelay H to bank contact g. Incidental to the operation of relay G itsupper winding will be closed through its contacts to ground, causingsaid relay G to remain actuated. Upon the next digit, '7,v being sentthe-shaft wipers willbe rotated to the 7th contact. Ground may now betraced through contacts on relay D, through winding of relay K,

through contacts on relay J, through wiper b,

over bank contact a to the lower winding of relay H, causing said relaysH and K to become actuated. Relay K for the purpose as previouslydescribed, and relay H for the purpose of extending ground through itscontacts through contacts on relay R, through off-normal contacts to therelease magnet of the selector. Upon release magnet of said selectorbecoming actuated the shaft and wipers will be restored to normalposition,

through contacts on relay J, through wiper b,

thereby disconnecting from any subsequent switches that may be up andassociated. Incidental to the shaft wipers being restored to normal,ground will be opened to the upper winding respectively of relays F, G,and H and to the winding of relay J in the following manner:The saidground may be traced from contact on relay B through contacts on relayM, through offnormal contacts, through contacts on relay E to contactson relays F, G, H an J. Should the digit, 6, have been sent in lieu ofdigit, 7, the shaft and wipers would have been rotated to the 6thcontact. Ground may now be traced from contacts on relay D throughwinding on relay K,

over bank contact, to the winding of relay L, causing said relays L andK to become actuated. Relay K for the purpose as previously describedand relay L for the purpose of extending ground through its contacts,through contacts on relay J to the winding of relay E, causing thelatter relay to become actuated. Upon relay E becoming actuated theground to the winding of relays F, G, H and J respectively will beopened, causing any of the said relays which may be actuated to berestored to normal. It will be noted that in this case relay H was notactuated, therefore the shaft of the selector of Fig. 1 is notdisturbed. Relays G and H are given a slow actuating characteristic (byslugging their cores with copper, for example) to render theminoperative to short applications of ground applied to their respectivelower winding poles as from wiper 12 passing over bank contacts f or gin restoring, while relay J is actuated.

Assuming that thirteen impulses are sent to 110 relay A, ground will beextended from back contact of said relay through the various relaycontacts to the rotary magnet as shown in the lower figure of Fig. 1,stepping the shaft wipers to the thirteenth rotary contact. Ground maynow be traced from contacts on relay D through winding of relay K,through contacts on relay J, through and remain so in a mannerpreviously described.

If the digits 357 are now sent from the impulse sending device theaction of the directive switch shown in the lower. part of the figurewill be the same as when the said digits 3--57 were sent from theimpulse sending device after sending twelve impulses to the relay A asdescribed, with this diiferencez-Upon relay H becoming actuated groundwill be extended from contacts on said relay H, through contacts onrelay R, through contacts on relay C to the lower winding on relay M,causing the latter relay to become actuated and remain so by reason ofground being extended from contacts on relay B, through contacts onrelay M to the lower winding of said relay M. Incidental to theoperation of the relay M repeating coil S will be included in the linecircuit between the line terminals and the line wipers. The circuit fromthe minus terminal will be by way of lower inside contact of relay M,right hand windings of the repeating coir S, upper inside armature ofrelay M to the plus line terminal. A circuitcan also be traced from theline wiper d", lower contacts of relay A, upper contacts of relay D,lower middle armature of relay M, left hand winding of re- 150

